Field of the Invention
The present invention relates to protection devices for integrated circuits (ICs), and in particular to electrostatic discharge (ESD) protection devices for integrated circuits (ICs).
Description of the Related Art
The semiconductor integrated circuit (IC) industry has experienced rapid growth. Technological advances in IC materials and design have produced generations of ICs where each generation has smaller and more complex circuits than the previous generation. These circuits may be sensitive to electrostatic discharge (ESD) currents. Thus, ESD protection devices are utilized to prevent and reduce damage to an IC caused by ESD currents.
Conventionally, n-type metal oxide semiconductor (NMOS) transistors have been widely used as primary component in ESD protection circuit in semiconductor integrated circuit devices. However, while existing n-type metal oxide semiconductor (NMOS) transistors functioning as ESD protection devices have been generally adequate for their intended purposes, they have not been entirely satisfactory in every respect.